1. Field of the Invention
The present invention relates to magnetic resonance scanning apparatus for imaging parts of a human head comprising a plurality of RF coils configured to receive an RF signal. In particular, the invention relates to neurological imaging apparatus.
2. Description of the Related Art
In a magnetic resonance imaging system for imaging parts of a human head, it is known to have RF (radio frequency) transmitting coils which transmit RF pulses to the head, and separate RF coils configured to receive the consequently emitted RF signals from the various tissues of the head.
Typically, the receiving RF coils form an array of small sized coils surrounding the head of a human subject. In recent years, a technique referred to as parallel imaging has been developed which allows each coil in an array to provide a different signal, and thereby provide further spatial information and reduce required scanning times. Such coil arrays are configured on a rigid circular former that surrounds the head giving reasonable clearance to allow the head good access, and therefore spaced away from the head, typically on a diameter of 27 cm or more, or they are based on dome shaped rigid structures that cover the top of the head but not below the eyes. One continuing problem with such RF receiving coils is the less than optimal signal to noise ratios of the signals they produce.
A further problem with existing RF receiving coils is the claustrophobic effect they can have on the human subject, due to their appearance over their face.
Yet another problem with such receiving coil arrays is that they generally rely on the human subject to keep their head stationary during the several minutes it takes to perform the scan.